ABU AD DUHUR, Syria — The rebels huddled before darkness near the edge of the Syrian air force base. They were about 40 men, hiding beside small buildings on the flatlands south of Aleppo.

Each man carried little more than a rifle and several dozen cartridges. They had gathered for an effort that illustrated the lopsided nature of the fight for Syria: lightly armed men trying to remove Syria’s attack jets from the skies.

Roughly two months into this important yet scarcely documented battle, Syria’s antigovernment fighters have succeeded in laying siege to the heavily fortified Abu ad Duhur air base. They have downed at least two of the base’s MIG attack jets. And this month they have realized results few would have thought possible. Having seized ground near the base’s western edge, from where they can fire onto two runways, they have forced the Syrian air force to cease flights to and from this place.

“We are facing aircraft and shooting down aircraft with captured weapons,” said Jamal Marouf, a commander credited by the fighters with downing the first MIG-21 here. “With these weapons we are preventing aircraft from landing or taking off.”

This is a significant setback for the government in the northern region, where rebels had already strengthened their position with homemade bombs, making roads too perilous for military vehicles to passand restricting the military’s movements.

But air power has remained a large advantage for President Bashar al-Assad, whose air force has pounded many cities and towns.

For the rebels, managing to deny the use of this airfield has undermined the government’s ability to exert its full authority in some parts of the country. It has also improved the morale of fighters who remain severely outgunned.

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Rebels have blocked Syria’s use of the Abu ad Duhur base.Credit
The New York Times

The rebels’ boldness, and their success, have not been painless. The army units inside the base have tanks, artillery and mortars. When attacked, the soldiers often respond by firing barrages of high-explosive rounds into the nearby town, in what amounts to a tactic of collective punishment against civilians. The effects are evident in the center of town, where block after block of buildings have been shattered. “This is the army, taking revenge,” said another fighter, Abu Razaq.

The events at Abu ad Duhur form another telling chapter of the uprising’s evolution, and for the tit-for-tat fight between the government and its adversaries.

The crackdown by the Assad government has descended in stages since it started last year. It began with arrests but quickly shifted into a bloody campaign by loyalist militias and a conventional army using mortars, artillery and tanks. This summer, as the campaign slowed in the face of swelling rebel ranks and roadside bombs, the government escalated again. It turned loose helicopters and then jets to attack rebels and their neighborhoods.

After the government moved its battle to the sky, at least hundreds of fighters from the mountains diverted some of their attention from the remaining army outposts near their homes and began infiltrating into the lowlands. Armed with a paltry assortment of weapons, they began hunting the aircraft that were hunting them.

Mr. Marouf, 37, is from Deir Sonbul, a village in Jebel al Zawiya, an area of rolling mountains where mosques and Muslim cemeteries stand beside Roman ruins and where olive groves cloak the slopes. Before the war he had been a construction contractor in Lebanon.

Now he is one of the rebels’ most prominent field commanders, his stature elevated in part by YouTube videos in which he is seen striding among the flaming wreckage of MIGs to stand over the bloodied remains of Syrian pilots still strapped to their parachutes. In one video he declared that if the world would not protect Syrians by enforcing a no-fly zone, then the rebels would create a no-fly zone themselves. That statement was fired in part by adrenaline, made moments after knocking a Russian-made jet from the sky.

In an interview after last Friday’s prayers, Mr. Marouf offered a more measured view and an assessment heard throughout the rebel-held zones. The Syrian opposition, he said, needs antitank weapons and shoulder-fired antiaircraft missiles, which would help the rebels defeat the government’s armor and ground its planes. Then he again offered a confident declaration.

“If they send us these, we will destroy this regime in less than 30 days,” he said.

The West has been reluctant to provide such arms, and rebels said Arab states had followed the West’s lead and not provided them either. (Although a few old SA-7 antiaircraft missiles have been spotted in rebel videos, these sightings have been rare, and the missiles have yet to be a significant factor in the conflict.)

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The tail section of a Syrian Air Force jet downed by the rebels near the Abu ad Duhur Air Base.Credit
Bryan Denton for The New York Times

Judging from what Mr. Marouf’s fighters carried as they moved around the air base’s western flank, the missiles have not appeared here, either. These men are woefully equipped. Most have only rifles. Ammunition supplies are lean.

The few heavier weapons visible — including a BMP armored vehicle, a Russian-made 14.5-millimeter machine gun and two mortar tubes — were all captured from government forces or purchased from corrupt army units, Mr. Marouf and two of his subcommanders said.

With the weapons they do have, the fighters have managed to overrun scores of mountain checkpoints, to sever the road linking Damascus and Aleppo, and to turn a once-secure military airfield into a forlorn and besieged outpost.

Exactly how many MIGs have been shot down around this air base is unclear. Fighters gave different tallies, ranging from three to six. But the rebels’ video, checked against interviews with fighters, make clear that at least two MIG-21’s had been downed, and a government transport plane taxiing on the runway about 10 days ago was turned back under fire.

The first jet was crippled in late August by Mr. Marouf using a 14.5-millimeter machine gun mounted on a truck bed, several fighters said. Until then, the rebel actions at the airport had been bold, but not necessarily effective.

As the aircraft burst into flame, the pilot ejected and the rebels opened fire on him as he slowly descended. Everything had changed. The fighters had punished the aircraft that were dropping bombs on their villages. An enemy once beyond reach had been hit. Emotions soared.

“It was indescribable,” said Abu Azab, who leads the Voices of the Right Brigade, one of the fighting groups that swear allegiance to Mr. Marouf. “We were hiding from the snipers, but after the MIG was hit we were jumping up and shouting ‘Allahu akbar!’ and we forgot about the snipers.”

Several days later, a second MIG-21 was hit, this time by a sniper rifle, the rebels said. It crashed and burned. A third aircraft, a MIG-23, crashed a few days later after being struck by heavy machine-gun fire, the rebels said.

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Mr. Marouf, second from left, is one of the rebels’ most prominent field commanders.Credit
Bryan Denton for The New York Times

In what seems the enduring competition among rebels seeking credit and outside financial support, various groups have said they were involved in these downings, boasting of them to journalists.

But only Mr. Marouf and his groups are seen in the videos firing on the aircraft and then wandering the flaming wreckage of the government’s jets. And they have a battlefield trophy rare to this brand of war — the shattered tail section of a MIG-21, which they carted off to Deir Sonbul.

Still, the battle for Abu ad Duhur has not come without its puzzles, its limits, or its costs.

On some days aircraft arrive from other bases to bomb or strafe the rebels and try to relieve the siege. Sometimes the base’s soldiers are resupplied, rebels said, by helicopters that hover high overhead and then risk a swift, spiraling descent and quick escape.

These sorties point to a larger picture: While the Syrian air force is under strain, and Abu ad Duhur is at risk of being overrun, other air bases are firmly in government control. The government’s air-to-ground campaign goes on. And the fight for Abu ad Duhur remains fierce.

Protective cover is hard to find near the base, which sits on a bare agricultural plain. The government’s soldiers know many places where rebels hide.

Moments after the fighters prayed at dusk among buildings at the base’s southwestern edge, the army struck. It shelled the rebels with mortar fire, forcing many of them to scatter and seek cover beside walls. Explosions followed them, as if the pattern of this fight had been set weeks ago.

The rebels said that eventually they would claim the base, capturing more weapons, including aircraft now idled in hangars or near the runways. That possibility has presented them with a conundrum: should they seek the destruction of the grounded aircraft, or try to protect them?

Riad Darwish, 24, a college student who joined the fighters, offered one view: “We are trying not to destroy the aircraft,” he said. “They are our aircraft, and we have pilots who are ready.”

Correction: September 28, 2012

An article on Thursday about Syrian rebels’ efforts to neutralize the country’s air force rendered incorrectly a comment by Jamal Marouf, a rebel commander. He said that if the rebels are supplied with antitank weapons and shoulder-fired antiaircraft missiles, they “will destroy this regime in less than 30 days.” He did not say “in not less than 30 days.”

A version of this article appears in print on September 27, 2012, on page A1 of the New York edition with the headline: Rebels Make Gains in Blunting Syrian Air Attacks. Order Reprints|Today's Paper|Subscribe